Growing UserControl Size with Style Trigger? - wpf

Question

I would like to cause a custom UserControl to grow by a multiplier when an "IsSelected" DP is set to true. My current XAML looks like this:
<ctrl:MyBaseControl x:Class="MyDemo.Controls.MyCustomControl"
...>
<ctrl:MyBaseControl.Resources>
<Style TargetType="{x:Type ctrl:MyCustomControl}">
<Setter Property="BorderBrush" Value="White" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="BorderThickness" Value="2" />
<Setter Property="Width" Value="340" />
<Setter Property="Height" Value="260" />
</Trigger>
</Style.Triggers>
</Style>
</ctrl:MyBaseControl.Resources>
<Border>
<StackPanel>
...
</StackPanel>
</Border>
In the above sample, "MyBaseControl" extends UserControl, and defines the IsSelected DP.
This code just plain isn't working at the moment, which is one of my issues. The other is that I would like to grow the Width/Height for a certain amount (for example: 0.10) instead of setting it to a hard number. This way I can set the size when I define the control at the source.
Thanks for any help!
ADDITION CODE:
MyBaseControl Code:
public abstract class MyBaseControl: UserControl
{
public static readonly DependencyProperty IsSelectedProperty =
DependencyProperty.Register(
"IsSelected",
typeof(Boolean),
typeof(MyBaseControl),
new PropertyMetadata(null));
public MyBaseControl() : base() { }
#region Properties
public Boolean IsSelected
{
get { return (Boolean)GetValue(IsSelectedProperty); }
set { SetValue(IsSelectedProperty, value); }
}
#endregion Properties
}
MyCustomControl Code:
public partial class MyCustomControl: MyBaseControl
{
public static readonly DependencyProperty IconProperty =
DependencyProperty.Register(
"Icon",
typeof(ImageSource),
typeof(MyCustomControl),
new PropertyMetadata(null));
public static readonly DependencyProperty BlurbProperty =
DependencyProperty.Register(
"Blurb",
typeof(String),
typeof(MyCustomControl),
new PropertyMetadata(null));
public MyCustomControl()
{
InitializeComponent();
}
#region Properties
public ImageSource Icon
{
get { return (ImageSource)GetValue(IconProperty); }
set { SetValue(IconProperty, value); }
}
public String Blurb
{
get { return (String)GetValue(BlurbProperty); }
set { SetValue(BlurbProperty, value); }
}
#endregion Properties
}
Example of working trigger on internal elements:
<Style TargetType="{x:Type Border}">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctrl:MyCustomControl}}, Path=IsSelected}" Value="True">
<Setter Property="BorderThickness" Value="5" />
</DataTrigger>
</Style.Triggers>
</Style>

Answer 1

Try this
<ctrl:MyBaseControl.Resources>
<Style TargetType="{x:Type ctrl:MyCustomControl}">
<Setter Property="BorderBrush" Value="White" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="BorderThickness" Value="2" />
<Setter Property="RenderTransform" >
<Setter.Value>
<ScaleTransform ScaleX="1.1" ScaleY="1.1" />
</Setter.Value>
</Setter>
<Setter Property="RenderTransformOrigin" Value="0.5, 0.5"/>
</Trigger>
</Style.Triggers>
</Style>
</ctrl:MyBaseControl.Resources>